Sen. Debbie Stabenow, D-Mich., greets pregnant women and new mothers in the Senate reception room before the start of a news conference on repealing or defunding the Affordable Care Act.

Oh, baby! You could end up paying a whole lot more for health insurance if you plan on — and actually end up — having a kid.

The Republican bill to replace Obamacare could lead to women in some states having to pay more than a whopping $1,000 per month extra for their health insurance plans if they want coverage for maternity care.

The bill would also cause some women to end up paying "thousands of dollars" extra on deductibles and other out-of-pocket health charges when they get pregnant and deliver a baby, according to an analysis.

One of those amendments, designed to lower premiums for some customers who purchase individual health plans, was added to attract support for the bill from conservatives.

The amendment would allow states to apply for waivers for insurers to let them charge people with pre-existing health conditions higher prices for coverage than healthier people who also buy insurance coverage outside of their job.

It also would allow insurers in states that get waivers to strip out certain minimum health benefits that Obamacare currently requires them to include in their health plans.

The CBO on Wednesday said that before the Affordable Care Act, or Obamacare, became law, there were just 18 states that required insurance plans to offer maternity care as part of their coverage.

The report said, "States that previously mandated fewer benefits would be more likely to apply for a waiver" to allow insurers to drop such currently mandated benefits if the Republican bill becomes law.

As a result, the CBO said, people living in states that eliminated maternity coverage as a required benefit, along with other services, "would experience substantial increases in out-of-pocket spending on health care or would choose to forego the services."

"In particular, out-of-pocket spending on maternity care and mental health and substance abuse services could increase by thousands of dollars in a given year for the nongroup enrollees who would use those services," the report said. Nongroup customers are people who get insurance from a private plan outside of a job.

The CBO noted that in some states where maternity care would be eliminated as an essential health benefit, insurers could end up offering women a so-called rider to their insurance plans to cover maternity care, at extra cost, on top of the regular monthly premium.

"Insurers would expect most purchasers to use the benefits and would therefore price that rider at close to the average cost of maternity coverage, which could be more than $1,000 per month," the report said.

The CBO noted that "the average cost of pregnancy care and delivery is about $17,000 for women with private insurance coverage."

But "either type of rider would result in substantially higher out-of-pocket health-care costs for pregnant women who purchased insurance in the nongroup market," the report said.

The report from the CBO sparked sharp criticism of the bill from advocacy groups.

The CBO "analysis ... confirms what we already know: the so-called American Health Care Act is a cruel attack on the health and well-being of women and families," said Andrea Miller, president of the National Institute for Reproductive Health. "Twenty-three million Americans would lose coverage under this sorry excuse for a replacement for the Affordable Care Act."

"Calling the AHCA a 'health care' bill is an oxymoron — it would drastically impede access to health care for the people who need it most," Miller said.

Miller said that passage of the bill "would have a severe impact on women's health care and their families' economic stability."

Dr. Anne Davis, consulting medical director of Physicians for Reproductive Health, said the report shows that the GOP bill "still takes insurance for millions of families off of the table."

"Comprehensive reproductive health care would still move out of reach, especially for millions of low-income people, because of this bill's attacks on Medicaid, Planned Parenthood and abortion coverage," Davis said.